I missed a lot of 3DS games in the last years, but I am eager to play a big game on the small screen again
I am going to travel a lot per train in the next weeks. I want to visit friends, families and do some hiking trips. I am not in the mood to read a book the whole time and want to play something.

A fast-pace game à la Mario Kart is not very good while travelling. I need something more relaxing such that I can look out of window every time I want. However, Ace Attorney is fun but then I could just read a book instead..

I thought, that Fire Emblem could be the perfect fit, but I do not see trough the many 3DS games in the series now. The last Fire Emblem is played was Path of Radiance in 2006. Do you recommend, one of the Fire Emblems for me? Or maybe an other series and game?

-a Pokémon
-Yoshi's Woolly World
-a Harvest Moon/Story of Seasons
-Link-a-Pix
-a Puzzler World (PW XL is a cheap DSiWare with a stupid amount of content, including many link a pix puzzles and hundreds and hundreds of word searches)
-any of the Picross E games.
-Farming Simulator (the most recent one)
-one of the fire emblems, of which there's probably more on the 3DS than in any other console ever. You have Awakening, Conquest, Birthright, (The third fates path), Shadows of Almia, Warriors (spin off), and Sacred Stones if you get an ambassador 3DS.
-an Etrian Odyssey.

There's many many turn based rpgs in the system and other laid back games to try.

-one of the fire emblems, of which there's probably more on the 3DS than in any other console ever. You have Awakening, Conquest, Birthright, (The third fates path), Shadows of Almia, Warriors (spin off), and Sacred Stones if you get an ambassador 3DS.

Oh yeah Animal Crossing is excellent, and you can even unlock full featured mini games, Panel de Pon/Puzzle League and a turn based island survival game, both of which would be good enough on their own.

Fire Emblem Awakening is an outstanding game on 3DS. Animal Crossing New Leaf Welcome Amiibo is also very relaxing and fun. Despite what @lunt claims, Pokemon XY or Pokemon ORAS are both great titles, and Pokemon Red/Blue/Yellow/Gold/Silver/Crystal are all also on the virtual console.